MODELING THE STRESS STATE OF THE BACKFILLING MASS WITH DIFFERENT PHYSICAL AND MECHANICAL PROPERTIES

2021 ◽  
pp. 7-18
Author(s):  
Mykhailo Petlovanyi ◽  
◽  
Kateryna Sai ◽  
Keyword(s):  
Mechanical Properties ◽  
Numerical Modeling ◽  
Stress State ◽  
Physical And Mechanical Properties ◽  
Practical Significance ◽  
Mining Operations ◽  
Mining Depth ◽  
Compressive Stresses ◽  
A Value ◽  
Backfilled Stopes

Purpose. Analytical researches of the stress state of the backfilling stopes with different physical and mechanical properties using numerical modeling to determine possible zones of stability losses and predict their failure. Methods. Numerical modeling of the formation of stresses around a high stopes was carried out for the conditions of mining iron ore reserves in the depth intervals of 740-1040 m of the Pivdenno-Bilozerske deposit, where mining operations are actively carried out using the finite element method in the SolidWorks 2016 software package with reliable substantiation of the parameters of the developed geomechanical model. Results. Numerical simulation of the stress state of the backfilling mass are carried out at variable values of the modulus of its elasticity and the mining depth. It was found that with the existing actual physical and mechanical properties of the backfilling mass during the development of the Pivdenno-Bilozerske deposit, the danger of its failure is predicted at depths of more than 890 m. In the center of the filling array, the stress values change linearly, and at the junction of the roof with the side of the backfilled stopes – polynomial. It was found that an increase in the modulus of elasticity of the backfilling mass allows to reduce the compressive stresses only at the junction of the roof with the side of the backfilled stopes to a value of 800 MPa. Scientific novelty. With an increase in the depth of development, despite an increase in the elastic modulus of the fill, the values of stresses increase, which eliminates the need to increase it with a decrease in the mining depth it was found. Practical significance. The results obtained make it possible to correct the technology of formation of a backfilling mass in the primary stopes, taking into account the formation of stresses on its contour and, with an increase in the mining depth, to form a backfilling mass with viscoplastic properties.

Effect of benzoyl treatment on the performance of sugar palm/kenaf fiber-reinforced polypropylene hybrid composites

2021 ◽  
pp. 004051752110432
Author(s):  
S Mohd Izwan ◽  
SM Sapuan ◽  
MYM Zuhri ◽  
AR Muhamed
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Hybrid Composites ◽  
Physical And Mechanical Properties ◽  
Morphological Properties ◽  
Fiber Reinforced ◽  
Kenaf Fiber ◽  
A Value ◽  
Hydrophobic Behavior ◽  
Sugar Palm Fiber

The main purpose of this work is to investigate the effect of benzoyl treatment on the performance of sugar palm/kenaf fiber-reinforced polypropylene hybrid composites. Water absorption tests were carried out to confirm the effect of benzoylation treatment toward fabricating a more hydrophobic behavior of the hybrid composites. Both treated and untreated composites that have 10 wt.% of fiber loading with three different fiber ratios between sugar palm and kenaf (7:3, 5:5, 3:7) were analyzed. Physical and mechanical properties such as tensile, flexural, and impact strength were determined from this study. Morphological properties were obtained using scanning electron microscopy (SEM). It was found that the tensile strength of sugar palm/kenaf-reinforced polypropylene hybrid composites was improved with the treatment of benzoyl with a value of 19.41 MPa. In addition, hybrid composite with treated sugar palm and kenaf fiber T-SP3K7 recorded the highest impact and flexural strength of 19.4 MPa and 18.4 MPa, respectively. In addition, SEM demonstrated that surface treatment enhanced the mechanical properties of the hybrid composites. Overall, it can be suggested that benzoyl-treated composites with a higher volume of kenaf fiber than sugar palm fiber will improve the mechanical characteristics of the hybrid composites.

An Experimental Study on Effect of T-Joint’s Root Gap on Welding Properties

2017 ◽  
Vol 863 ◽  
pp. 323-327 ◽  
Author(s):  
Yustiasih Purwaningrum ◽  
Panji Lukman Tirta Kusuma ◽  
Dwi Darmawan
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Testing Machine ◽  
Low Carbon Steel ◽  
Physical And Mechanical Properties ◽  
Optical Microscope ◽  
Low Carbon ◽  
Weld Metals ◽  
A Value ◽  
Welding Properties

The aimed of this research is to investigate the effect of T-Joint’s root gap on physical and mechanical properties of weld metal. Low carbon steel were joined in T-joint types using MIG (Metal Inert Gas) with variation of root gap. The root gap used were 0 mm, 3 mm and 6 mm. The physical properties examined with chemical composition, microstructure and corrosion using optical microscope. The mechanical properties were measured with respect to the strength and hardness using Universal testing machine and Vickers Microhardness. The results show that the highest value found in welds with a gap of 3 mm with a value of 163.57 MPa. Hardness value is directly proportional to the tensile strength of the material. The highest value found in welds with root gap of 3 mm, followed by root gap of 6 mm, and 0 mm Hardness values in the welding area is higher than the parent metal and HAZ because the number of Si, Mn and Cu elements in the welding metals are bigger than base metal. Weld with all variation of root gap have a good corrosion resistance because the corrosion rate in welds with various root gap have a value below 0.02 mmpy. Microstructure of weld metals were Accicular ferrite, Widmanstatten ferrite, and grain boundary ferrite, while microstructure of base metal and HAZ were ferrite and perlite.

scholarly journals Pengaruh Penambahan Abu Serbuk Kayu Dan Serbuk Batu Bata Berdasarkan Uji Konsolidasi Dan Waktu Penurunan Tanah Lempung

2021 ◽  
Vol 9 (2) ◽  
pp. 124-128
Author(s):  
Ranggaski Yoan Vianus ◽  
Mohammad Ikhwan Yani ◽  
Fatma Sarie
Keyword(s):  
Mechanical Properties ◽  
Clay Soil ◽  
Physical And Mechanical Properties ◽  
Central Kalimantan ◽  
One Dimensional ◽  
Consolidation Test ◽  
A Value ◽  
Brick Powder ◽  
Consolidation Coefficient ◽  
Mixed Material

The waste from the wood and brick industry in Central Kalimantan is largely unused. The research objective aims to analyze the physical and mechanical properties of clay soil in the Tumbang Rungan area of ​​Palangka Raya City, Central Kalimantan and the effect of adding sawdust ash and brick powder based on the consolidation test and the time of subsidence of the clay soil using the Terzaghi one-dimensional consolidation method with the addition of a mixture of 2 variations 2,5%, 5% and 7,5%. Tests conducted are to obtain the consolidation reduction value (Sc) and the consolidation coefficient value (Cv). The results of the study using a mixture of sawdust ash and brick powder obtained changes in the Sc and Cv values ​​of the original soil. The original soil has a value of Sc (e) = 0.291 cm and Cv (t50) = 0.01913205 cm²/s, Cv (t90) = 0.031062161 cm²/s and the addition of a mixture of 5% variation of material has decreased the value of Sc (e) = 0.203 cm and Cv (t50) = 0.00722173 cm²/s, Cv (t90) = 0.011679143 cm²/s. The effective mixture variation for adding mixed material to clay is a variation of 5%.

scholarly journals Studying the similarities of deformation properties of leather materials in the process of creating a model of shoes

2020 ◽  
Author(s):  
Maryna Leshchyshyn Mykolaivna ◽  
Svitlana Stepanivna Garkavenko ◽  
Antonina Ivanivna Babich
Keyword(s):  
Mechanical Properties ◽  
Marketing Research ◽  
Physical And Mechanical Properties ◽  
Experimental Tests ◽  
Practical Significance ◽  
Preliminary Measurement ◽  
Parameters Selection ◽  
Wet Friction ◽  
Deformation Properties ◽  
The Individual

Determination of values and dependencies of deformation and physical and mechanical properties of materials of shoe models and finished products. According to the results of theoretical, analytical and marketing research, a number of experimental tests of materials have been carried out to prove the practical significance of the work, namely tests for: deformation of the vamp part of the product, uniaxial and biaxial stretching, bending, dry and wet friction, adhesion, elongation and tearing. There has been established the nature of the distribution of the total elongations of the samples of the vamps cut from different areas of the leather, as well as the ability of the leather material to be formed when improving the shape of the product or changing the shape of the shoetree. The processes of deformation of the vamp part of shoe blanks, physical and mechanical properties of different groups of modern materials and values analysis of similarity of their deformation properties have been studied. There has been created a working model-transformer for carrying out preliminary measurement of clients’ feet at the individual order. The expediency of these works has been proved experimentally. A working version of a model-transformer for foot measurements has been made and as a result of the works approbation, a sample of shoes has been made. The ergonomic properties of the manufactured footwear have been improved due to the use of materials with enhanced physical and mechanical properties. The article investigates the deformation of the most vulnerable vamp part of the men's model of a typical model, as well as the physical and mechanical characteristics of leather materials for manufacturing models and shoes of this type. Providing high quality and comfort of footwear, accuracy of parameters selection of foot measurement, zones of beams and achievement of form stability of footwear with a top from genuine leathers has been predicted.

scholarly journals Physical and mechanical properties of the rocks of the Starobinsky deposit forming the Third potash layer and its roof

2021 ◽  
Vol 65 (4) ◽  
pp. 484-494
Author(s):  
A. B. Petrovsky ◽  
V. Ya. Prushak ◽  
E. A. Lutovich
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Geological Structure ◽  
Mining Operations ◽  
The Third ◽  
Composition And Structure ◽  
Mining Conditions ◽  
The Stability ◽  
Roof Falling ◽  
Main Factor

The geological structure and the physical-mechanical properties of rocks composing and overlapping the Third potash formation in the areas of the mine field mine No. 4 JSC Belaruskali, which are scheduled to practice, are studied. The geological sections of the Third potash layer and its roof were built, the thickness of sylvinite and halite layers was measured, the roof falling of the rocks of the layer with a height of up to 20 m was assessed, and the type of immediate roof was determined by the composition and structure of its constituent rocks. It was established that the strength under uniaxial compression of both sylvinite and halite layers for the areas under consideration differs slightly. Therefore, to solve engineering problems of ensuring the stability of mine workings and to calculate fastening parameters, strength values averaged over the groups of layers can be used that correlate well with the percentage of weak and clay interlayers. The same applies to Poisson’s ratio, the values of which for various layers of formation are slightly different and can be taken by their averaging. It is shown that the main factor that negatively affects the strength of rocks occurring in the roof of the Third potash seam is the presence of weak and clay interlayers, which increases with depth. The introduction of the obtained results allows us to improve the calculation accuracy of securing mining parameters, to reduce the costs of their maintenance, and to improve the safety of mining operations in developing the Third potash formation in complex geological and mining conditions.

scholarly journals Analysis of efficiency of drilling equipment use in mining operations

2021 ◽  
Vol 315 ◽  
pp. 02018
Author(s):  
Yuriy Masaev ◽  
Vladislav Masaev ◽  
Yuriy Drozdenko
Keyword(s):  
Mechanical Properties ◽  
Energy Intensity ◽  
Physical And Mechanical Properties ◽  
Structural Features ◽  
Ore Deposits ◽  
Mining Operations ◽  
Drilling Equipment ◽  
Wide Range ◽  
Mine Workings ◽  
Underground Method

When developing coal and ore deposits by underground method, it is necessary to carry out a large volume of preparatory mine workings using drilling and blasting operations. Minerals are found in rocks under various conditions and their physical and mechanical properties change in a wide range. Under such conditions, it is necessary to use drilling machines this different to the principle of action and structural features. The article considers geometric parameters of roc cutters, peculiarities of drilling modes, affecting energy intensity and drilling productivity in rocks with different strength coefficient.

Study on Physical and Mechanical Characteristics of Q2 Loess and Micro-Structure Properties in Li-Shan

2014 ◽  
Vol 1065-1069 ◽  
pp. 1846-1849 ◽  
Author(s):  
Ying Wang ◽  
Pan Pan Yang
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Practical Significance ◽  
Basic Unit ◽  
Micro Structure ◽  
Basic Characteristics ◽  
Microscopy Techniques ◽  
Xi’An City ◽  
Scanning Electron ◽  
Physical And Mechanical Characteristics

The physical and mechanical properties and microstructure of Q2loess are of great theoretical and practical significance. Through studying these properties which Q2loess samples are taken in the Xi'an city of Lin-tong District of Mount Li, the results show that: (1)Natural water content, wet density, liquid and solid index, shear strength, collapsible coefficient compressive modulus; (2)By means of the scanning electron microscope to study the picture of the loess micro-structure, there are some preliminary understanding of micro-structure’s basic characteristics; (3)Using scanning electron microscopy techniques to observe the loess micro-structure, As the performance of the loess micro-structure’s basic unit-body and its arrangement form, the loess micro-structure is the reflection of its physical and mechanical properties, Meanwhile the change of physical and mechanical properties also show the unstability of the loess micro-structure.

scholarly journals Mechanical Characterization of Angustifolia Kunth and Rayada Amarilla Guadua Bamboo

2019 ◽  
Vol 303 ◽  
pp. 03002
Author(s):  
Brayan García ◽  
Camila Preciado ◽  
Mónica Bedoya ◽  
Oscar Mendoza
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characterization ◽  
Construction Material ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Fiber Direction ◽  
Three Point Bending ◽  
Compressive Stresses ◽  
Cylindrical Samples

Guadua is a Colombian endemic type of grass belonging to the bamboo family. It can be considered an alternative construction material due to its physical and mechanical properties, as well as a sustainable source of timber due to its fast growing process and high availability in tropical countries. The Guadua is composed by the stem petiole or lower part, the stem base, and the stem. In turn, the stem is divided into sections separated by diaphragms that form knots, called culms. The distance between knots and the structure of the longitudinal fibers in the culms depend on the age of the plant. This implies a difficulty when determining the mechanical properties of the stem, since there are not specific standards for this purpose. In this work the mechanical properties of young samples of Angustifolia Kunt and Rayada Amarilla Guadua, of around 6 years of growth, were characterized. To account for the natural variability introduced by the presence of diaphragms, cylindrical and prismatic samples were extracted without knot, with one knot in the middle, and with one knot at each end. Cylindrical samples were used to measure compressive strength parallel to the fiber direction, while prismatic samples were used to measure tensile strength also parallel to the fiber direction and flexural strength by three point bending. Methodologies from conventional construction materials were adapted for this purpose. The obtained results allowed concluding that the Guadua samples present different mechanical properties depending on the position of the knots. Samples with a knot in the middle are more resistant to compressive stresses, while the samples without knot are more resistant to flexural and traction stresses. The samples with one knot at each end presented a more balanced behavior, being efficient when exposed to compression, traction and flexural stresses.

scholarly journals Strength coefficient estimation by indirect methods

2021 ◽  
Vol 1 (3) ◽  
pp. 28-35
Author(s):  
Arkadii N. Avdeev ◽  
Elena L. Sosnovskaia ◽  
Aleksandr Iu. Bolotnev
Keyword(s):  
Mechanical Properties ◽  
Modulus Of Elasticity ◽  
Physical And Mechanical Properties ◽  
Acoustic Properties ◽  
Mining Operations ◽  
Indirect Methods ◽  
Strength Coefficient ◽  
Coefficient Estimation ◽  
Non Destructive ◽  
Gas Bearing

Introduction. In exploration, construction, and mining operations it is necessary to assess the physical and mechanical properties of rocks. However, laboratory rock tests are expensive, time-consuming, and require a large number of quality rock samples. There is a problem of rapid evaluation of physical and mechanical properties by indirect, non-destructive methods. The problem is considered on the example of one of the basic properties, the strength coefficient according to Protodiakonov's scale. Research methodology included the analysis of the main indirect methods of determining the strength coefficient based on strength, elastic and acoustic properties of rocks on the grounds of statistical empirical relationships of V. V. Rzhevskii, G. Ia. Novik, L. I. Baron; K. L. Ter-Mikaelian, A. I. Beron, and M. M. Protodiakonov. The most promising methods based on non-destructive laboratory tests of modulus of elasticity and longitudinal wave velocity are selected. Results and conclusions. The strength coefficient was calculated by several methods on the example of siliceous sandstones, selected from the exploration well of the gas-bearing field. The results were compared with each other and with cadastral references and materials. The most optimal for calculations were the dependences of V. V. Rzhevskii, G. Ia. Novik, and L. I. Baron when evaluating the strength coefficient by the modulus of elasticity, and the dependences of A. I. Beron and L. I. Baron when calculating based on acoustic characteristics.

scholarly journals Parametric analysis related to dimensioning of tubular steel columns filled with concrete in a fire situation

2022 ◽  
Vol 15 (2) ◽  
Author(s):  
Fábio Masini Rodrigues ◽  
Armando Lopes Moreno Júnior ◽  
Jorge Munaiar Neto
Keyword(s):  
Mechanical Properties ◽  
Numerical Modeling ◽  
Temperature Field ◽  
Moisture Content ◽  
Numerical Models ◽  
Physical And Mechanical Properties ◽  
Sensitivity Study ◽  
Steel Tube ◽  
Structural Elements ◽  
Steel Columns

ABSTRACT For the dimensioning of structural elements in fire situation, simplified equations and parameters are commonly used in analytical equations or numerical models. More complex equations or simplified values can be chosen by the designer for determine materials properties in high temperature in numerical models, however, numerical modeling can be quite sensitive to the variation of some of the physical and mechanical properties. In this paper, the sensitivity of the numerical model in relation to the values according to the level of simplification chosen was evaluated, presenting an analysis in relation to the results found to contribute to the choice of these parameters and presenting the indications found in the literature. In this sense, this work presents a study of sensitivity to the variation of the values of steel and concrete properties, presented in the Eurocode and Brazilian standards, in addition to the moisture content and emissivity of the surface exposed to fire, for the dimensioning, in a fire situation, of steel tube columns, of circular and square section, filled with concrete. The studies were carried out via numerical modeling developed in the software ABAQUS. It was verified that the resulting emissivity values equal to 0.7 or 0.8, recommended in the literature, are conservative, and the choice of either does not bring significant changes in the temperature field obtained for the structural elements under analysis. It was also verified that the concrete moisture content is a relevant aspect for the formation of its temperature field, also affecting, but to a lesser extent, the steel temperature. Regarding the physical and mechanical properties of the materials, this sensitivity study suggests the adoption of the values from the equations presented in Eurocodes, without simplifications, and with the specific heat and thermal conductivity of the concrete, adopted in accordance with the Eurocode 4.

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